Constellation-multiplexed transmitter and receiver

ABSTRACT

A device of dynamic communication of information allows, on the average, non-integer bits per symbol transmission, using a compact code set or a partial response decoding receiver. A stream of selectable predetermined integer bits, e.g., k or k+1 data bits, is grouped into a selectable integer number of bit vectors which then are mapped onto corresponding signal constellations forming transmission symbols. Two or more symbols can be grouped and further encoded, so that a symbol is spread across the two or more symbols being communicated. Sequence estimation using, for example, maximum likelihood techniques, as informed by noise estimates relative to the received signal. Each branch metric in computing the path metric of a considered sequence at the receiver is weighted by the inverse of the noise power. It is desirable that the constellation selection, sequence estimation and noise estimation be performed continuously and dynamically.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. Non-Provisional ApplicationSer. No. 10/045,283, filed Oct. 18, 2001, now U.S. Pat. No. 7,254,167,issued Aug. 7, 2007, which is a continuation-in-part of U.S.Non-Provisional application Ser. No. 09/430,466, filed Oct. 29, 1999,now U.S. Pat. No. 6,553,063, issued Apr. 22, 2003, which claims benefitto U.S. Provisional Application No. 60/106,481, filed Oct. 30, 1998, allof which are incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an apparatus and method for communicatinginformation using fractional bits-per-symbol signaling rates responsiveto communication channel conditions.

2. Description of the Relevant Art

There exist applications for which it is desirable to transmittransmission symbols that each is composed of a number of informationbits which may not represent an integer. The signal constellationsassociated with such transmissions symbols, then, corresponds tonon-power-of-two constellation sizes and/or non-integer constellationsizes.

What is needed is a device that affords fractional bits per symboldigital communication approaching a maximum allowable bit rate yet doesso in an efficient manner permitting use of compact code sets, or use ofa partial response receiver. Before proceeding with a description ofexemplary embodiments, it should be noted that the various digitalsignaling concepts described herein—with the exception, of course, ofthe inventive concept itself—are all well known in, for example, thedigital radio and voiceband data transmission (modem) arts and thus neednot be described in detail herein. These include such concepts asmultidimensional signaling using 2N-dimensional channel symbolconstellations, where N is some integer; trellis coding; fractionalcoding; scrambling; passband shaping; equalization; partial response;Viterbi, or maximum-likelihood, decoding; Quadrature AmplitudeModulation (QAM); Orthogonal Frequency Division Multiplexing (OFDM),etc.

SUMMARY OF THE INVENTION

The invention herein provides communication devices affordingnon-integer bits per symbol digital communication at bit ratesapproaching optimality for a given set of constraints, using a compactcode set or utilizing partial response receiver. In general, the deviceswhich embody the present invention, can include a transmitter, areceiver, or both. These devices manipulate arriving data from a databit form to a transmission symbol form in a data transformer,advantageously using knowledge of one or more data channel conditions todynamically and continuously adjust the constellations used to representthe transmitted data. Successive transmission symbols each can contain avarying selectable predetermined integer number of data bits, asgoverned by a constellation selection controller that is connected withthe data transformer. Successive symbols can be transmitted at differenttime stamps or at different frequency locations. A performance metricestimate can be used to determine which constellation is to be used. Areceiver using a sequence estimation technique can optimally decode thereceived signals given the condition that (i) the soft-decision symbolsat the receiver are correlated through the employed channel codingand/or through the introduction of defined partial channel response, and(ii) there exists knowledge of the signal-to-noise ratio (SNR) metric ofeach soft-decision symbol. Having these techniques, a transmitter, forexample, can transmit on the average non-integer information bits persymbol, say between k and k+1, with the multiplexing of a firstconstellation, representing a first selectable predetermined integernumber of data bits, e.g., k bits per symbol, and a secondconstellation, representing a second selectable predetermined integernumber of data bits, e.g., k+1 bits per symbol, such that the desirednon-integer information-bit-per-symbol transmission is achieved. It isdesired that such multiplexing be done continuously and dynamically.Furthermore, the digital communication facilitated by the inventionherein is not limited to temporal sequence transmission (i.e., the timedomain) but also can be used in the frequency domain, or both.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an block diagram illustrative of an exemplary embodiment ofthe present invention.

FIG. 2 is a block diagram illustrative of a first exemplary embodimentof the present invention, in the form of a transmitter.

FIG. 3 is a block diagram illustrative of a first exemplary embodimentof the present invention, in the form of a receiver implementingsequence and noise estimation.

FIG. 4 is a block diagram of another exemplary embodiment of atransmitter illustrative of a trellis encoding implementation as anoption.

FIG. 5 a is a block diagram illustrative of a exemplary transmitterembodiment intended for single symbol encoding.

FIG. 5 b is a block diagram illustrative of a exemplary transmitterembodiment intended for multiple symbol encoding.

FIG. 6 is a block diagram of another exemplary embodiment of a receiverillustrative of an implementation of demodulation, sequence and noiseestimation.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The present invention provides for processing communication data using anumber of information of data bits per transmission signal, which may bea non-integer, with realizable integer or power-of-two constellationsizes. A forward error correction (FEC) code with a proper code rate canbe added such that the information bit rate could further be adapted toa signal constellation size that is an integer or a power-of-two.Depending on the required resolution of the average information bitsbeing transmitted in each symbol, a set of FEC codes can be employed toaccommodate the desired code rates. However, this resolution cantranslate into an undesirably large set of embedded codes needed toachieved the target transmission metrics which, for rate-adaptiveapplications, complicates the design and rate adaptation procedures. Inthe invention herein, as few as one fixed trellis code may be used toachieve the desired resolution on the transmission information bits persymbol, simplifying the associated device designs and communicationprotocols. In the cases where FEC coding is not desirable, or notnecessary, the desired resolution on the transmission bits per symbolstill can be optimally accommodated through the use of a sequenceestimator at its receiver to decode a pre-defined partial responseformed for the soft-decision symbols at the receiver.

One application for which this communication data processing may bedesirable is rate-adaptive communication service. In a rate adaptiveservice in which the maximum allowable bit rate is decided beforeservice sessions start and a non-integer bits per symbol might berequired to achieve this maximum bit rate. By doing so, non-integerinformation bits per symbol can be transmitted.

For the purposes herein, the term channel noise will include additivewhite Gaussian noise, colored Gaussian noise, or both; scintillationnoise; shot and impulse noise; all forms of channel attenuation; signalfading and distortion; interference such as intersymbol interference;and any other entity that acts to deviate or disperse the data signalactually received from the data signal originally transmitted, bothadditive and multiplicative, regardless of stationarity ororthogonality.

An exemplary embodiment of the present invention is seen in FIG. 1.Communication device 1 is interposed into a data channel which isrepresented by communication channel input data stream 2 andcommunication channel output data stream 3. The data channel cantransmit both the desired information as well as undesirable channelnoise that is imposed upon the data stream due to one or more channelconditions.

Communication device 1 includes data transformer 4 and controller 5, andcan be representative of a transmitter or a receiver. Data transformer 4manipulates information between data bits and transmission symbols. Inan instance where device 1 represents a transmitter, input data stream 2can be the data bits intended to be transmitted and output data stream 3can be the transmission symbols transmitted through the data channel. Ina case where device 1 represents a receiver, input data stream 2 can bethe transmitted symbols as detected at the receiver, and output datastream 3 can be the recovered data bits which correspond to the databits entering a transmitter. Device 1 is not constrained to operatesolely in the time domain, but may operate in other domains including,for example, frequency domain. Also, device 1 is operative where data isboth transmitted and received in both time and frequency domains.

According to the present invention, the predetermined integer number ofdata bits contained in a transmission symbol is selectable, responsiveto the channel condition. The selection of the selectable predeterminedinteger number of data bits in a transmission symbol can be governed bycontroller 5. It is desired that the channel condition to whichcontroller 5 responds, and by which the selectable predetermined integernumber of data bits is selected and processed by data transformer 4, bea preselected channel condition metric. Desirable metrics for therepresentation of channel condition include the signal-to-noise ratio ofthe received symbol and/or the power of the noise in a received symbol.The desirable metric may further be restricted by preselectedconstraints such as, for example, a bit error rate (BER). Data bitselection also can be driven by master controller 8, which may beexternal to device 1, and which itself may be responsive to a state ofthe data channel, such as the SNR of the received signal. Where device 1is a transmitter, controller 8 may be operably connected to acorresponding receiver. It also is desired that channel state monitoringbe continuous, and that selection of the selectable predeterminedinteger number of data bits used to form a transmission symbol beadaptive to a present condition of the data channel.

Having described the general inventive concept, a more detailedembodiment will now be described. In FIG. 2, transmitter 11 includesdata transformer 12 and constellation selection controller 18. Datatransformer 12 can include bit parser 13, encoder and constellationmapper 17, and constellation table 16. Constellation selectioncontroller 18 employs control signal 15 to govern the operation ofparser 13, as well as the operation of encoder and mapper 17. Forexample, relative to the operation of bit parser 13, controller 18 cangovern the selection of the selectable predetermined integer number ofdata bits per bit vector; relative to the operation of encoder andmapper 17, controller 18 can govern the selection of the constellationalphabet used during a particular interval, and the level of redundancyand correlation imposed upon the transmission symbols prior totransmission via channel output data stream 19.

In FIG. 3, receiver 24 includes a noise estimator 28, a sequenceestimator 26, a constellation selection controller 31, a constellationtable 34, and a parallel-to-serial converter 36. It will be readilyapparent that data transformer 29, which can include estimator 26, table34 and converter 36 is functionally equivalent to data transformer 4 inFIG. 1. Although noise estimator 28 is illustrated to be external todata transformer 29, yet within receiver 24, it also may be groupedwithin data transformer 29, or even be external to receiver 24. It isdesirable that constellation selection controller 31 be responsive to achannel condition, such as the signal-to-noise ratio or strength ofreceived symbol and noise 25.

The transmission symbols carried upon the received signal 25 are knownto be corrupted, or tagged, by some amount of channel noise. Noiseestimator 28 is employed to quantify the amount of channel noise presentin signal 25. Noise estimate 37 is received by sequence estimator 26such that a reasonably good estimate of the transmission symboloriginally transmitted to receiver 24 can be derived. Although oneskilled in the art would recognize that many implementations of receivedsignal estimation can be used to effect recovery of the transmittedsignal, the skilled practitioner also would realize that it is desirableto employ a maximum likelihood sequence estimator (MLSE) as sequenceestimator 26 in receiver 24 for optimized data reception. One such MLSEcan be realized with a Viterbi decoder. A MLSE typically is used fordecoding a convolutional code, a trellis code, as well as receivedsymbols with partial response, and can be advantageous in the presenceof channel noise such as intersymbol interference. In decoding aconstellation-multiplexed (CM) signal, such as described herein, a MLSEcan take advantage of the SNR information of each symbol at the receiverand produce a maximum likelihood estimation of CM signals that canapproach optimality.

Constellation selection controller 31 can assign each received symbol inthe MLSE with an appropriate constellation mapping, and its associateddata bits per transmission symbol. Based on the assigned constellationmapping, not only does the MLSE compute path metrics of a receivedsymbol accordingly, it also can scale the branch metrics according tothe maximum likelihood estimation criterion. As above, constellationselection controller 31 directs parallel-to-serial converter 36 tooutput corresponding data bits in each symbol. It is desirable forsynchronization to be established between the constellation selectioncontroller of a transmitter and the constellation selection controllerof a corresponding receiver.

Another exemplary embodiment of the present invention, in the form ofconstellation-multiplexed transmitter 40, is illustrated in FIG. 4. Heretransmitter 40 includes a bit parser 41, trellis code encoder 45 as anoption, constellation mapper 47, constellation tables 48, modulator 51,and constellation selection controller 49. Furthermore, controller 49itself may be governed by master control 53. The master control could bea corresponding controller on a corresponding receiver.

Without loss of generality, it is useful to illustrate the principles ofthe present invention with a specific example where k and p/qinformation bits are transmitted per symbol, and where k, p and q areintegers, and p is smaller than q. The illustration is by way of threeexamples. For each example, it is assumed that the interval over whichthe average data bit rate is to be measured includes the communicationof eight symbols; that the average data bit rate may be a non-integer;that each symbol is composed of a single data bit vector; and that thedata bit vector is composed of a selectable predetermined integer numberof data bits, say k and k+1 data bits.

In the first example, when the data bit rate is desired to be, forexample, 7.073 data bits per transmitted symbol, preferred embodimentsof the present invention can select the predetermined integer number ofdata bits, e.g., k data bits, to be 7 data bits, and the secondpredetermined integer number of data bits, e.g., k+1 data bits, to be 8data bits. To achieve the desired 7.073 data bits per transmitted symboldata bit rate, bit parser 41 can selectively and adaptively partitionthe stream of incoming data bits 42 into seven seven-bit data bitvectors, and one eight-bit data vector, each of the data bit vectorsbeing grouped as a transmission symbol, and mapped to a signalconstellation of competent configuration. In this case, one power-of-twosignal constellation (2³=8 signal values) can be used for alltransmission symbols. The resulting predetermined data bit rate is about7.125 data bits per transmitted symbol (k=7, p=1, q=8), easilyaccommodating the 7.073 data bits per transmitted symbol.

In the second example, it is desired that the data bits per transmittedsymbol be increased to about 7.771 data bits per transmitted symbol, forexample, in response to improved channel conditions. Bit parser 41 canselectively and adaptively partition the stream of incoming data bits 42into one, seven-bit data bit vectors (k=7), and one eight-bit datavector (k+1=8), each of the data bit vectors being grouped as atransmission symbol, and mapped to a signal constellation of competentconfiguration. In this case, one power-of-two signal constellation (2³=8signal values) can be used for all transmission symbols. The resultingpredetermined data bit rate is about 7.875 data bits per transmittedsymbol (k=7, p=7, q=8), easily accommodating the 7.771 data bits pertransmitted symbol.

In the third example, should the desired data bits per transmittedsymbol over the measuring interval again be increased, for example, inresponse to further improved channel conditions, and a data bit rate ofabout 8.198 data bits per transmitted symbol is desired, bit parser 41can selectively and adaptively partition the stream of incoming databits 42 into six, eight-bit data bit vectors (k=8), and two nine-bitdata vector (k+1=9), each of the data bit vectors being grouped as atransmission symbol, and mapped to a signal constellation of competentconfiguration. In this case, two power-of-two signal constellations(2³=8 signal values and 2⁴=16 signal values) can be used, the first,smaller signal constellation accommodating eight-bit transmissionsymbols; the second, larger signal constellation accommodating eight-bittransmission symbols. The resulting predetermined data bit rate is about8.250 data bits per transmitted symbol (k=8, p=2, q=8), easilyaccommodating the 8.198 data bits per transmitted symbol.

The foregoing, being solely for the purpose of illustration, does notlimit the invention herein to measuring intervals having eight symbols,symbols being composed of seven, eight, or nine bits, transmissionsymbols being composed of a single data bit vector, or require anyparticular signal constellation configuration to be used. In view of thepresent disclosure, skilled artisans could easily adapt the variousembodiments of the present invention, whether a transmitter, a receiver,a system, or a portion thereof, to achieve a desired data bit rate bycomposing data bit vectors having selectable predetermined integernumber of data bits, and grouping the data bit vectors to achieve thedesired ends.

At the transmitter 40, bit parser 41 can receive an input bit stream 42at a rate of k and p/q bits per symbol. Bit parser 41 selectivelypartitions incoming data bits 42 into bit vectors 43. It is desired thatthe partitioning be performed continuously. Parser 41 sends bit vector43 composed of a selectable predetermined integer number of data bits,for example, k or k+1 data bits, to an optional trellis code encoder 45under the direction of constellation selection controller 49. Afterencoder 45 imposes a predetermined correlation between successive outputbit vectors 43 from bit parser 41, the resultant encoded vectors 46 arethen mapped to corresponding transmission symbols 50 by way ofconstellation mapper 47.

Constellation mapper 47 can employ constellation table 48 to map eachvector into transmission symbol 50 that is a member of one or morepreselected symbol alphabets which themselves can correspond with asymbol constellation. Constellation selection controller 49 cancontinuously govern the selectable predetermined integer number of databits grouped into a bit vector according to a particular predeterminedpattern. In the exemplary embodiment of the invention herein, eachpredetermined pattern is representative of a preselected signalconstellation, having a selectable predetermined integer number of databits per symbol, for example, k or k+1 integer bits per symbol.

Note that constellation mapper 47 can map vectors 43 directly from bitparser. In this case, the system is an uncoded one, and no correlationmay be imposed on transmitted symbols. The correlations will be imposedon received symbols at its receiver by forming a pre-defined partialresponse for the received symbols. However, in some embodiments, whereit is desirable to employ encoder 45, bit parser 41 first directs thebit vector to encoder 45. Encoder 45 imparts a pre-determinedcorrelation among data, in this case, between successive output vectors.

Constellation selection controller 49 can govern the selection betweenselectable predetermined integer numbers of data bits, e.g., k and k+1data bits, in bit vector 43 from bit parser 41, such that the averagetransmitted bits per symbol 50 is k and p/q 41 e.g., 3.25). Controller49 also can direct the trellis code encoder 45, or constellation mapper47, or both, to choose the desired constellation size based on thenumber of bits to be transmitted via the transmission symbol at hand.Where it is desired to further process transmission symbols 50 intosignals 52 better suited for a particular transmission format, modulator51 may be used. Responsive to modulator 51, consecutive symbols can betransmitted at different time stamps, or at different frequencylocations, or both.

As in previous embodiments of the present invention constellationselection controller 49 is desired to be responsive to a sensed channelcondition 54; or to a master control 53 which may be external totransmitter 40, for example, from a corresponding receiver.

The optional trellis code used in a system according to the inventionherein could be a single symbol code or a multi-symbol code. FIG. 5( a)shows an encoder 50 that implements a single-symbol trellis code inwhich c data bits 51, out of each k or k+1 selectable predeterminedinteger number of data bits 52, provided as data bit vectors by parser57, are encoded to c′ data bits 53 through, for example, a convolutionalencoder 54. Constellation mapper 55 converts the encoded data bits 53and uncoded data bits 51 into a transmission symbol 56 in the desiredinformation format. FIG. 5( b) shows an example of an encoder 60implementing an m-symbol trellis code, in which data bit parser 66provides a selectable predetermined integer number of data bits, e.g., kor k+1 input data bits, corresponding to a single transmission symbol,with m symbols 67 being buffered in symbol buffer 62 before beingencoded. Among these selectable predetermined integer number of inputbits of the m transmission symbols 67, c data bits 65 are encoded to c′data bits 68 again, for example, through encoder 69 which may be aconvolutional encoder. These c′ data bits 68 are combined with uncodeddata bits 64 and are mapped in constellation mapper 63 into mconsecutive transmission symbols 71 in preparation for transmission.Note that the m consecutive transmission symbols do not necessarily usethe same constellation.

In FIG. 6, receiver 75, which is preferred to be a maximum-likelihoodsequence estimator receiver, includes a demodulator 76, noise estimator77, sequence estimator 78, demapper 79, constellation tables 80,parallel-to-serial converter 81, and constellation selection controller82. Demodulator 76 recovers received soft-decision symbols r_(m) 83 fromreceived signal 84, which signal 84 contains original transmissionsymbols 92 from constellation-multiplexing transmitter 91, corrupted bychannel noise 93. Transmission symbols 92 may be transmitted in signal84 at different time stamps, different frequency locations, or both. Inthe case where the transmission symbols 84 were not first encoded in thetransmitter 90, it is desired that demodulator 76 forms a partialresponse on the received symbols so that a defined correlation, whichmay exist between received soft-decision symbols r_(m) 83, can beutilized. It is desirable for noise estimator 77 to associate a noiseestimate metric 89 with each soft-decision symbol 83; the noise estimatemetric being, for example, a noise power estimate metric or a SNRestimate metric.

Sequence estimator 78 determines recovered data symbolsa_({circumflex over (k)},m) 86 on the basis of the predeterminedcorrelation among consecutive symbols 83 output by demodulator 76. It isdesired to incorporate noise estimate metric 89 in extracting a sequenceof symbols 86 from symbols 83. Indeed, it is desired to use a MLSE assequence estimator 78, and that noise estimate metric 89 be used tocompute the likelihood metric of each considered sequence. Where asequence is selected to be the most likely transmitted sequence based onthe likelihood metric, the quality of recovered data symbols 86 canapproach optimality, in the maximum likelihood sense.

One method for describing the operation of MLSE 78 is as follows:

In general, it is desirable for sequence estimator 78 to find a sequence{a_({circumflex over (k)},m)} at its output such that either of thefollowing noise-power weighted Euclidean distances is minimized:

$\sum\limits_{m}\;\frac{\left( {r_{m} - a_{k,m}} \right)^{2}}{N_{m}}$ or$\sum\limits_{m}\;\frac{{{SNR}_{m}\left( {r_{m} - a_{k,m}} \right)}^{2}}{S_{A_{m}}}$where

each a_({circumflex over (k)},m)ε{a_(k,m)}≡A_(m)

m is a symbol index;

k is an alphabet index;

{circumflex over (k)} is the decided alphabet index;

A_(m) is a set of alphabets used for symbol m;

N_(m) is the estimated noise power associated with symbol r_(m);

SNR_(m), is the SNR associated with the symbol r_(m); and

S_(A) _(m) is the average signal power associated with the alphabet setused for r_(m).

This is because in the presence of, for example, noise whose powervaries across different symbols, the maximum likelihood decodingessentially consists of finding that particular path through the trelliswith the minimum-weighted-squared-Euclidean distance to the receivedsequence, where, in computing the path metric, each branch metric isweighted by the inverse of the noise power associated with thesoft-decision symbol. It is preferred that theminimum-weighted-squared-Euclidean distance of the particular path be asubstantially minimum noise-power-inversely-weighted-squared-Euclideandistance. Recovered data symbols 86 are received from MLSE 78 bydemapper 79 and, in conjunction with constellation tables 80, maps arecovered symbol 86 onto a data bit vector 87, the size of which vectormay vary between successive symbols. Tables 80 typically corresponds tosimilar constellation tables in transmitter 90. As bit vectors 87 aregenerated by demapper 75, parallel-to-serial converter 81 convertsvectors 87 into a bit stream 88 that corresponds to the data bit streamoriginally input to transmitter 90. Similar to the operation ofconstellation selection controller 49 in FIG. 4, constellation selectioncontroller 82 can inform demodulator 76, sequence estimator 78, demapper79, and parallel-to-serial converter 81 of the pertinent details of theconstellation being implemented at a particular moment, such as thecurrent symbol alphabet and the number of bits in recovered symbol 86.As with a constellation selection controller 91 in transmitter 90, it isdesirable for controller 82 to allow different sets of symbol alphabetsand provide a variable number of bits in a symbol, responsive to achannel state. It is desirable to provide some form of synchronizationbetween the constellation selection controller 91 in transmitter 90, andthe constellation selection controller 82 in receiver 75.

Although the invention is illustrated herein as being implemented withdiscrete functional building blocks, e.g., trellis encoders,constellation mappers, etc., the functions of any one or more of thosebuilding blocks can be carried out using one or more appropriateprogrammed processors, digital signal processing (DSP) chips, etc. Itshould be noted that the principles of the invention are also applicableto other areas of communications. For example, the principles of theinvention can also be applied to the design of modems for use in datacommunications, to fading channel applications, and so on.

The various constellations, bit and baud rates, and other parametersare, of course, merely illustrative. Moreover, the invention can bedescribed herein in the context of multiple amplitude/multiple phaseconstellations, conventionally known as “QAM”, it is equally applicableto other types of constellations, such as constant amplitude/multiplephase constellations, such as M-PSK and M-DPSK. The device and methodaccording to the method herein provides for symbols to be transmittedacross the channel at different time stamps (such as using a QAMtechnology); at different frequency locations; or through a combinationof both (such as using an OFDM technology). Additionally, the inventiondescribed herein may be applied to contexts of voiceband datatransmission, cellular mobile radio, digital microwave radio, satellitecommunications, wire communications, wireless communications, and thelike.

The foregoing merely illustrates the principles of the invention, and itwill thus be appreciated that those skilled in the art will be able todevise various alternative arrangements which, although not explicitlydescribed herein, embody the principles of the invention within thespirit and scope of the following claims.

1. A communication device comprising: a. a data transformer operablycoupled with a data channel, the data transformer manipulating the datachannel between data bits, a data bit vector, and a transmission symbol,the data bit vector having a selectable predetermined integer number ofdata bits, the transmission symbol containing a selectable integernumber of the data bit vectors; and b. a controller operably coupledwith the data transformer, the data transformer being responsivethereto, the controller adaptively selecting the selectablepredetermined integer number of data bits, and the selectable integernumber of data bit vectors to communicate data through the data channelat a predetermined data bit rate in response to a data channelcondition, wherein each of the selectable integer plurality of data bitvectors has one of a first predetermined integer number of data bits anda second predetermined integer number of data bits represented therein;and wherein the data transformer, responsive to the controller,reversibly groups ones of the first predetermined integer number of databits into selected ones of the selectable integer number plurality ofdata bit vectors and ones of the second predetermined integer number ofdata bits into selected others of the selectable integer numberplurality of data bit vectors in the response to the data channelcondition.
 2. The communication device of claim 1, wherein thetransmission symbol is comprised of one data bit vector having one of afirst predetermined integer number of data bits and a secondpredetermined integer number of data bits represented therein.
 3. Thecommunication device of claim 2 wherein the data transformer selectssuccessive ones of a plurality of data symbols according to one of apreselected coding method and an unencoded method, in the response tothe controller, the controller being responsive to the data channelcondition.
 4. The communication device of claim 3, wherein the datatransformer dynamically selects a predetermined correlation betweensuccessive ones of the plurality of data symbols in the response to thecontroller, the controller being responsive to the data channelcondition.
 5. The communication device of claim 4, wherein the datatransformer continuously selects a predetermined correlation betweensuccessive ones of the plurality of data symbols in the response to thecontroller, the controller being responsive to the data channelcondition.
 6. The communication device of claim 5, wherein the datatransformer selects a predetermined correlation between successive onesof a plurality of transmission symbols in the response to the channelcondition, according to a preselected coding method.
 7. Thecommunication device of claim 6, wherein the preselected coding methodis constellation-multiplexed coding.
 8. The communication device ofclaim 7, wherein the preselected coding method isconstellation-multiplexed coding.
 9. The communication device of claim1, wherein the data channel condition comprises at least one of receivedpower, signal-to-noise ratio, and an input from a master control.